Ok back in June my car stalled. Dealer says plugs...wires...and coils. All that gets done and car stalls again in July. This time they say do the engine decarb. Did that and all was good until yesterday. Stalled again 4 months later!

Ok so i thought maybe this is a catalytic converter problem but i just went through emissions here to get my tags and passed fine. If that was the problem i wouldnt pass emissions would i? So i really just dont know what it could be and why its only happening every now and then? Back in the summer i thought it was due to the heat but yesterday was only in the 60s here and i had been driving through town just fine until it suddenly decided to do it. Then afterwards it drives just fine? Its very strange how randomly it occurs.

Always happens when coming to a stop...the car starts to jerk and i instantly know its trying to stall. It feels like its clogged up or something cuz even when i punch the gas to try to keep it from stalling its as if im not even pushing the gas.

So im gonna just take it in and say keep it til u figure out whats going on i guess and rent a car. Nothing worse than stalling out in traffic in such a nice car! I love this car I just need to trust it!

 

Might be something with the fuel system or the engine is on its way out.
Have them do a compression test.

 

They say they have done the compression test. I was actually thinking if it was the fuel filter or something fuel related since it feels like its chocking itself out ya know?

 

Most fuel pump-filter combos last 60+K some have made it to 200K. When they usually fail is when you are at WOT in higher RPM's and it feels like your out of gas. Please give us the history on your car. The service it's had parts replaced. Type of driving it gets(long commutes, short trip), fuel used(reg or prem), ever flooded, mods installed. Just any thing that you can add. How many miles do you have? Have you cleaned your MAF sensor yet? Have you ever run any engine de-carbon cleaner to improve compression? You might need this to clean up the carbon buildup. I would add a can to your tank with just a quarter left of gas. Give it a good work out in the high RPM range under load till its real empty. Most here get a can of Seafoam($8 Walmart) or BG44K about $15-20 at auto shops. Some times this has to be done a few times. If this does help then you might want to pre-mix after. The "TSB" from Mazda that was performed before would work best. I would want to see the compression # myself. I hope you can save it!

 

Start with the simple and cheap "fixes"; 1) Make sure your air filter is clean. 2) As stated, clean the MAF sensor. 3) Also clean your e-shaft sensor and reset the profile (20 Brake Pedal Stomp Procedure). 4) Make sure your spark plugs are tight and the plug wires are firmly seated on the plugs and coils.

 

62k miles...it flooded once last January and was towed to the dealer. No mods are installed. Cleaned maf sensor and got new air filter in January. Spark plugs and wires are tight and were double checked by my friend. I did the decarbon myself using mazdas cleaner but I think I'm gonna do it again cuz the engine had cooled down before I got the treatment sucked in. No white smoke came out the tailpipe at all when I did it back in July.

 

Then #3 is all that is left before things get serious.

 

Something else to add I use to get about 260 to 280 miles per tank and now it's about 220 to 240 and I have always used premium gas.

 

If you followed the decarb procedure and did not get white smoke, I think that means the catalytic converter is failed. 8 oz of liquid hydrocarbons + functioning (hot) cat should equal smoke. Someone can correct me if I'm wrong!

I fogged the entire neighborhood when I decarboned mine.

 

But how could I pass emissions if I had a bad cat?

 

i have NOT read this thread, so this is a simple blind answer to the quote above....

the cat is 2 parts. the first section followed by the O2 sensor, followed by the rear(backup) section. the first section is failing, which you have determined because this causes the O2 sensor to report a CEL. but the second section of converter is still doing its job and you pass the sniffer(assuming its sniffer only)

not saying this relates to the OP, or that its realistic, but it could happen

 

I do not have a cel

 

Oh and when they do emissions here they plug in to the computer so it does not involve a probe being stuck in the tailpipe anymore

 

That is how you passed the emissions test.

 

compression test...

 

Ok so i did the engine decarb treatment again today and a little smoke came out but not much at all so i know its not full of carbon. Im gonna see what happens. If it tries to stall again I will take it in and let them see what they can figure out. I mean there is a list of things it can be and I suppose they are just gonna have to check it all out cuz im still under extended warranty!

I will def keep this updated in case other people out there are having the same issue!

 

UPDATE : So it tried to stall again today....and when i got home and put it in park i could hear the engine choking. I got out of the car and listened to the exhaust and u could hear it pop and at that moment is when the engine would choke. So thats def a misfire right? Has to have something to do with the fuel system i would think because i have new plugs...wires...coils...did engine de carb twice...cleaned MAF ...new air filter...i mean what else could cause the misfire?

 

Did you clean the e-shaft sensor and perform the NVRAM reset like Ray stated earlier?

 

Spend the $100 and get the compression test down. All will be revealed.
Railton

 

Why would it cost to get a compression test? Wouldnt that be something thats covered under extended warranty?

 

Have not cleaned the e-shaft no but i have reset before yes. We reset after the new spark plugs and wires and coils were installed.

 

Well, if it turns out the motor is duff then the dealer might not charge you for it but normally, No.
Railton